Hummer fan clutch installed

[big blue dsl]

Figured I would post up some pics of this installed in my burb, I have been running it for about a month no and am happy with it. The truck warms up quicker and I'm sure I picked up a little free hp. I used all the parts listed in the original thread discussing it and they all fit perfectly. The only part that needed modifying was the water pump pulley, the hummer's use a 3/4 inch spacer between the crank pulley and the damper, instead of spacing all of my bracketry out I had a machinist make a sleeve that made the pulley longer and we were in business. I used the aeroquip fitting to take the out of the power steering box to jic and then up to the solenoid.

The solenoid is a 12v one, if you look at the kascar website they list the part number for it and you can find 12v ones.

I wired it in with a relay, so that the fan is always off and the switches that I am using are all ground switches. I run 2 vintage air switches, a trinary switch that cycles the fan on and off when the ac wants it, which should improve ac performance. I put a temp switch in the thermostat outlet housing that turns the fan on at 205 and off at 195. And a manual override in the cab so I can lock it on when I want


I don't know how to upload pics on this site from my iPad but I will post a thread on the place

 

[Will L.]

What was the cost?

 

[WarWagon]

Congrats! I am sure a lot of us were kicking this idea around.

Only advantage I imagine over a dmax fan and a Kennedy clutch is being able to kick on before you hit 210 on the gauge hitting a hill flat out towing. It just eliminates the "slow" thermal spring response in a fan clutch.

How is the on-off-on-off feel of the clutch operation?

With the non-factory turbo the cooling need drops off so much I can't justify doing this myself anymore.

 

[big blue dsl]

Yea I'm sure it's a bit overkill but I wanted to see if it could be done, the clutch comes on and off really smooth I find that there is a 1 second delay before it engages due to exhausting the fluid but release is instant.

I have a hx40w as well and haven't towed my boat with it yet so will have to see how the temps do from there, we do make trips to bc though and that involves some serious hills, which kicked my a$$ last summer. I want to go back and go over the same roads again to see what we have gained

 

[guybb3]

I think this is one of the coolest mods ever!!!

 

[big blue dsl]

The cost was up there but I was more interested to see if it could be done,

The clutch cost 60 on eBay
The fan was 75 on eBay
The bolts and pulley from kascar were 120
The solenoid was 125 from a place called Arkansas turbo
Hoses and fittings I got from work for about 60
And the two temp switches were 60

I think it wound up being more than what a dmax fan and Kennedy clutch would have cost me but in my mind others that the lining wearing out in the clutch it will always work 100% it will never loose rpm like a viscous clutch would and like I said I was after the challenge to see if I could do it, like fitting dmax dual exhaust on my truck, working on it is my hobby just need to keep myself busy is all

 

[GM Guy]

so you just had a super deep dish pulley made to line the fan/water pump pulley back up with the rest of the accessories?

how did the fan fit? is it much bigger? any other fitment issues that required modifying, or does it fit in surprising well in a pickup/SUV body?

sounds pretty cool, hope it works well for you.

I personally wished they could do an air one like the horton clutches on the big trucks(probably not too practical) , or an electric one like the aftermarket, and I think OEM on the 6.0L PSD.

But, If the power steering engaged hummer clutch works well and looks sorta factory, than I guess it is the best option for the 6.5L

 

[big blue dsl]

Yep the sleeve made the pulley deep enough to line every thing back up and works awesome.

The fan fit like a glove no mods at all to the shroud at all, the onlything I did was drill a hole in the shroud for the bulkhead fitting for the hydraulic hose to the fan hub, so it fits surprisingly well in these bodies.

I looked at adapting an air one but they are wicked heavy and we have no air on our trucks so I figured that this would work better

 

[JayTheCPA]

I personally wished they could do an air one like the horton clutches on the big trucks(probably not too practical) , or an electric one like the aftermarket, and I think OEM on the 6.0L PSD.

Horton does have an electric clutch that works with the 6.5 but does not cross-reference it (last I checked); it is the same as the 7.3 PSD part. 6.0 PSD clutch will not fit as the screw for the clutch is a different size. I had noticed there was discussion of using the electric clutch that GM put on the Trailblazer (same concept as the 6.0 PSD), but that part looked like it had reliability issues on the gasser and not durable enough for the diesel.

Am surprised I had not found the Hummer clutch earlier as this might give a more economical path than the Horton.

In the end, am still casually working on how to install pusher fans up front to avoid using the engine fan just to cool the A/C condenser; ~10% hit to fuel economy from the condenser in my world is enough penalty and adding 100% load of the engine fan to boot is not where I prefer to go.

Back to the original topic, Awesome Job of the Hummer clutch install! :thumbsup:

 

[Twisted Steel Performance]

:nopics:

 

[JayTheCPA]

Ummm . . . There are pics, but they are over

on the place

 

[WarWagon]

I could write a book on the trailblazer PWM fan clutches. Cummins uses them in some applications, better brand and higher TQ rating needed for the fan pitch (load). The PWM fan isn't that easy or cheap to control.

To cool the AC condenser get a couple of the "pusher" fans that were an option on the 454 2500 pickups and 2500 burbs. 1993/1994 and will fit all years. You will have to move the trans/engine oil coolers or just one or the other for one fan setups. They generally went on the passenger side.

 

[THEFERMANATOR]

I could write a book on the trailblazer PWM fan clutches. Cummins uses them in some applications, better brand and higher TQ rating needed for the fan pitch (load). The PWM fan isn't that easy or cheap to control.

To cool the AC condenser get a couple of the "pusher" fans that were an option on the 454 2500 pickups and 2500 burbs. 1993/1994 and will fit all years. You will have to move the trans/engine oil coolers or just one or the other for one fan setups. They generally went on the passenger side.

And DODGE had more than there fair share of trouble out of there electric fan clutch on the CUMMINS. If you go to the DODGE boards you will see a lot of threads regarding people swapping in PSD fan clutches and fans to there CUMMINS after the electric portion got ripped off the front of the fan clutch.

 

[big blue dsl]

i run a fleet of super doodies and the guys in the shop are really good at changing the clutches and repairing the wiring....so that didn't seem like a good option for me, the trinary switch will cycle the engine fan whenever it wants it, i figured it has worked that way on heavy duty otr trucks for 20 years it should be ok on ours

 

[WarWagon]

And DODGE had more than there fair share of trouble out of there electric fan clutch on the CUMMINS. If you go to the DODGE boards you will see a lot of threads regarding people swapping in PSD fan clutches and fans to there CUMMINS after the electric portion got ripped off the front of the fan clutch.

Pages in the hot rod parts catalog have electric fans and clutch fans on the same page. The electrics read replace the unreliable HP robbing clutch fan. The clutch fans read replace the unreliable and low flowing electric fans. Mixing electric and viscus clutch fans has the unreliability of both. (Electrical problems and the clutch fan problems.)

The real advantage in the EV electro-viscus fan setup is instant lockup of the fan clutch when needed. On a cold startup the AC condenser can overheat esp out here as the radiator adsorbs heat and keeps the engine clutch fan off. It can take 30 min before the AC catches up. You can have the EV clutch at full lockup in 2 min flat. Not sure how Dodge did with the programming but GM FUBAR'd it on the Trailblazer. Tweaked the tables and got some cold air out of R134a on 121 degree days.

Then I found out the real problem was hot air coming over the top of the radiator and heating up the AC condenser. After sealing that off I reprogrammed the fan again for less fan...

Reprogrammable computer control of the fast responding variable speed fan with belt drive power is impressive. The early GM design/reliability issues and keeping the wires out of the fan do need work.

Electrics didn't flow enough air alone. Warmed up idling in traffic. Clutch fans flow 10,000 CFM with the hood closed through the stack, our diesel fans flow way more, and electrics are hard pressed for 5,000 CFM free standing. (No radiators, hood etc is free standing.)
Flex fan didn't flow enough at idle and was screaming at high RPM.
Clutch fan wouldn't lock in soon enough to cool down the undersized AC.

Best combo was a new fan clutch and a 12" electric fan strapped to the condenser that was wired to the compressor clutch. Better combo I learned later is a Dmax fan and low temp clutch with a pusher fan.

 

[JayTheCPA]

To cool the AC condenser get a couple of the "pusher" fans . . . will have to move the trans/engine oil coolers . . .

Had considered that, but the current options I generally see are to move the cooler under the bed (further back the cab in my case) where preference is to keep all the radiators / coolers in a place of natural air flow and hence why I am still on the hunt of how to do pusher fans. At the moment it is looking like a matter of spacing that the 94+ grills take away by moving the mesh closer to the coolers versus the 92 - 93 grills, so might do some fabrication work this summer to move the mesh flush with the rest of the faceplate.

 

[Jamin6.5]

I have a flex light electric pusher that i installed in my truck to help the a/c out. It works great. 12" pusher will fit with the stack in place. Still have the oil cooler and trans-cooler in the same places.